Finn writes:

Maybe, if I get hold of a end mill bit, I can "machine" the

rear bulkhead in

my drill press.

No way. Send me the box and I will do it for free except if I have
to farm out some parts for grinding. You pay for all parts
and shipping both
ways. I will need a new gear as no way can we salvage the
gear you have.
Or take it up to Tracy's and do it on his mill.

Finn, is your Ross bellhousing not machined on the back side, like mine?

I was thinking of adding a thrust bearing like your third drawing, adding a
plate to the back side of the bellhousing.

Chuck Dunlap

No, it's not. That's one of the reasons I'm very tempted to put the thrust plate
on the front side of the bulkhead. If I could just get some educated answers from
the engineer types on this list to the questions on minimum thickness of thrust
plate (I'm thinking 1/8" steel), minimum thickness needed for the pin (I think I
could go as low as 3/16") and consequences of using a thrust needle bearing
(designed to be piloted by the shaft) that's 1.5" ID instead of the 1.44" ID
(current shaft OD).

>From inside edge of support (8" circumference) for thrust plate to center of
thrustbearing race there's approx .5". How thick does the plate need to be to
support 1200 pounds?

2400 pounds over .72" (shaft radius) = 3333 pound/inch, over .028 sq inch (area
of 3/16" pin/bolt) would require 119000 psi bolt/pin shear strength, with a
safety factor of 2 (pin comes out through shaft and into sun gear at two points).
An AN3 bolt has 125000 psi tensile strength but is that also the shear strength?

I looked up the life of the 2mm needle bearing and it comes out to about 180
hours at 6500 RPM and 1200 pounds thrust.

I have 13 mm available between planet gears and unmachined bulkhead.

13 - 3.6 (thrust bearing and race washers) - 4.76 (3/16" pin) - 3.175 (1/8"
plate) = 1.47 mm left over for clearance around pin.

Finn

You are confusing the hell out of me stick to inches or metric.
Forget the pin. The pin can go anywhere on a new gear and shaft.
The thrust bearing can ride over them.
How thick is that seal? Are you sure about that 1/8 " seal 
counter bore depth? Take a picture.

Paul Lamar
 
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